Emission spectroscopy of negative hydrogen ion sources: From VUV to IR

The target parameters of negative ion sources regarding the current of extracted negative ions, the current of co-extracted electrons, the pulse duration, the duty cycle, and the availability of the system can be rather strict. Knowledge of plasma parameters such as the electron temperature and the electron density and also properties of molecules or photon fluxes can provide essential insights into the ion source physics needed for reaching the target parameters. Emission spectroscopy is a non-invasive tool enabling access to line-of-sight averaged values of plasma parameters. This paper gives an overview of the application of emission spectroscopy in the visible range, extended for long wavelengths to the near-IR and for short wavelengths to the vacuum ultraviolet (VUV)/UV range. The amount of information to be gained from measured emission spectra is directly correlated with the effort invested for calibrating the system. Examples are given, ranging from simple monitoring to the complex evaluation of molecular spectra and the determination of highly energetic photon fluxes in the VUV/UV range. Additional emphasis is laid on the population models needed for the interpretation of measured spectra.

The CardioOP-Data Clas (CDC)

Objectives: Self-directed and customized medical education programs are gaining importance in health care instruction. We prototypically implemented a repository-driven online computer system (CardioOP) for teleteaching in Heart Surgery. It supports authoring and multiple re-use of multimedia data for different user groups in different instructional applications and therefore requires a process of content management.

Methods: We defined objectives for a terminological system to support semantic, cross-media type annotation and retrieval of learning objects: domain completeness, German (natural) language processing, multi-user concepts, extensibility and maintenance, content based annotation and technical implementation. Existing terminologies (ICD10, READ V3, Snomed III, UMLS 1997, MESH) have been analysed according to these objectives.

Results: We found that the analysed terminologies did not meet our criteria sufficiently. Therefore, we developed a domain-specific thesaurus, the CardioOPDataClas (CDC). The application of the CDC within a database-driven authoring process using specifically developed tools is reported.

Conclusions: Metadata play an important role in the effective discovery and search, access, integration and management of educational multimedia data in medicine but so far, there is no terminology to support content management for instructional multimedia. We prototypically designed and applied a thesaurus for the CardioOP educational system. Additional work is needed to evaluate the system in terms of user-friendliness, concept coverage and information retrieval performance.

Enhancing the accuracy of the Fowler method for monitoring non-constant work functions

The Fowler method is a prominent non-invasive technique to determine the absolute work function of a surface based on the photoelectric effect. The evaluation procedure relies on the correlation of the photocurrent with the incident photon energy hν which is mainly dependent on the surface work function χ. Applying Fowler's theory of the photocurrent, the measurements can be fitted by the theoretical curve near the threshold hν⪆χ yielding the work function χ and a parameter A. The straightforward experimental implementation of the Fowler method is to use several particular photon energies, e.g. via interference filters. However, with a realization like that the restriction hν ≈ χ can easily be violated, especially when the work function of the material is decreasing during the measurements as, for instance, with coating or adsorption processes. This can lead to an overestimation of the evaluated work function value of typically some 0.1 eV, reaching up to more than 0.5 eV in an unfavorable case. A detailed analysis of the Fowler theory now reveals the background of that effect and shows that the fit-parameter A can be used to assess the accuracy of the determined value of χ conveniently during the measurements. Moreover, a scheme is introduced to quantify a potential overestimation and to perform a correction to χ to a certain extent. The issues are demonstrated exemplarily at the monitoring of the work function reduction of a stainless steel sample surface due to caesiation.

Fundamental studies on the Cs dynamics under ion source conditions

The performance of surface conversion based negative hydrogen ion sources is mainly determined by the caesium dynamics. Therefore, fundamental investigations in vacuum and plasma are performed at a flexible laboratory setup with ion source parameters. Studies on the influence of Cs on the plasma parameters of H2 and D2 plasmas showed that ne and Te in the bulk plasma are not affected by relevant amounts of Cs and no isotopic differences could be observed. The coating of the vessel surfaces with Cs, however, leads to a considerable gettering of hydrogen atoms from the plasma volume and to the decrease of ne close to a sample surface due to the formation of negative ions.

Controllable evaporation of cesium from a dispenser oven

This instrument allows controlled evaporation of the alkali metal cesium over a wide range of evaporation rates. The oven has three unique features. The first is an alkali metal reservoir that uses a dispenser as a cesium source. The heating current of the dispenser controls the evaporation rate allowing generation of an adjustable and stable flow of pure cesium. The second is a blocking valve, which is fully metallic as is the body of the oven. This construction both reduces contamination of the dispenser and enables the oven to be operated up to 300 °C, with only small temperature variations (<5 °C). By minimizing the temperature variation, the built up of the alkali metal at a cold spot is significantly hindered. The last feature is an integral surface ionization detector for measuring and controlling the evaporation rate. The dispenser oven can be easily transferred to the other alkali-metals.

Chronic atrial fibrillation: decreased actin expression in patients with chronic atrial fibrillation

AIM

Chronic atrial fibrillation (AF) is characterized by a severe contractile dysfunction and myolysis, which develops progressively. Myolysis and the remodelling of the cellular ultrastructure is associated with the replacement of sarcomeres by glycogen. The aim of our study was to determine if myolysis is characterized by a reduction in actin concentration.

METHODS

Right atrial samples from 18 patients undergoing elective cardiac surgery were excised and immediately frozen in liquid nitrogen. Eight patients had chronic AF (>3 months) and 10 patients were in sinus rhythm (SR). Actin concentration was determined by sodium dodecyl sulfate-polycrylamide gel electrophoresis (SDS-PAGE), Western blot and quantified by optical densitometry.

RESULTS

Immunoblot analysis demonstrated actin expression in all hearts. In myocardial samples from patients with chronic AF we found a 2.1 fold reduction in actin expression. (P<0.001)

CONCLUSION

The decrease in actin concentration via myolysis, might decrease energy consumption and be an additional mechanism for contractile dysfunction in chronic AF.

Disruption of the FA/BRCA pathway in bladder cancer

Bladder carcinomas frequently show extensive deletions of chromosomes 9p and/or 9q, potentially including the loci of the Fanconi anemia (FA) genes FANCC and FANCG. FA is a rare recessive disease due to defects in anyone of 13 FANC genes manifesting with genetic instability and increased risk of neoplasia. FA cells are hypersensitive towards DNA crosslinking agents such as mitomycin C and cisplatin that are commonly employed in the chemotherapy of bladder cancers. These observations suggest the possibility of disruption of the FA/BRCA DNA repair pathway in bladder tumors. However, mutations in FANCC or FANCG could not be detected in any of 23 bladder carcinoma cell lines and ten surgical tumor specimens by LOH analysis or by FANCD2 immunoblotting assessing proficiency of the pathway. Only a single cell line, BFTC909, proved defective for FANCD2 monoubiquitination and was highly sensitive towards mitomycin C. This increased sensitivity was restored specifically by transfer of the FANCF gene. Sequencing of FANCF in BFTC909 failed to identify mutations, but methylation of cytosine residues in the FANCF promoter region was demonstrated by methylation-specific PCR, HpaII restriction and bisulfite DNA sequencing. Methylation-specific PCR uncovered only a single instance of FANCF promoter hypermethylation in surgical specimens of further 41 bladder carcinomas. These low proportions suggest that in contrast to other types of tumors silencing of FANCF is a rare event in bladder cancer and that an intact FA/BRCA pathway might be advantageous for tumor progression.

Over-expression of IGF-related peptides in stenoses of native arteriovenous fistulas in hemodialysis patients

INTRODUCTION

Insulin-like growth factors (IGFs) are known to play an important role in atherogenesis. The aim of our study was to assess the local expression of IGF-related peptides in stenosed hemodialysis fistulas and compare these with their respective serum levels.

METHODS

We investigated 15 stenosed vein segments of primary arteriovenous fistulas, 29 non-stenosed control vein segments from uremic patients and 15 non-stenosed control saphenous vein segments. Immunohistochemistry was performed for IGF-I, insulin, IGF-binding proteins (IGFBPs)-1, -2, -3 and -4, the acid labile subunit (ALS) and type 1 IGF-receptor (IGF-R). Serum levels were measured by specific radioimmunoassays.

RESULTS

Compared to both control groups, a significantly higher expression of the following IGF-related peptides was seen in the stenotic (neo)intima: IGF-I, IGFBP-1, -2, -3, -4 and IGF-R; in the stenotic media: IGF-I and IGFBP-3 and in the endothelium of stenotic fistulas: IGF-I (all p<0.05). Staining against ALS and insulin was negative in all vessels. Serum IGF-I levels did not differ. Serum levels of IGFBP-1, -2, -3 and -4 were significantly higher in patients with renal disease (all p<0.05). There were no correlations between local and systemic IGF-related peptide levels. There were correlations of neointimal expression of IGF-I, IGFBP-1, -2, -3, -4 and IGF-R with both hypercellularity and the presence of inflammatory cells (p<0.05).

CONCLUSION

In the stenotic arteriovenous fistula of hemodialysis patients, expression of the peptides IGF-I, IGFBP-1, -2, -3, -4 and IGF-R was significantly increased and showed a positive correlation with neointimal inflammation and hypercellularity (all p<0.05). IGF-related peptides are most likely synthesized locally and might be involved in the initiation and/or progression of neointimal thickening of primary arteriovenous fistulas.

Impaired health-related quality of life in patients with chronic hepatitis C and persistently normal aminotransferase levels

A significant impact of hepatitis C virus (HCV) infection on health-related quality of life (HRQOL) has been previously described. However, comprehensive data on the quality of life in patients with chronic hepatitis C and persistently normal aminotransferase levels (PNAL) are currently not available. One hundred fifteen patients with chronic hepatitis C (45 with persistently normal aminotransferases and 70 with elevated aminotransferases) and 50 healthy subjects were enrolled. Emotional and psychological states were assessed by Profile of Mood States (POMS) scale and HRQOL was assessed by the 'Everyday Life' questionnaire (EDLQ), a validated questionnaire related to the SF-36 Health Survey. An impairment in HRQOL was observed in patients with chronic hepatitis C showing PNAL compared with healthy subjects with significant differences for the factor scores depression and anger in the POMS scale as well as for the items body, relationship to partner, self-confidence and zest of life in the EDLQ. No differences in any questionnaire were observed between patients with chronic hepatitis C showing PNAL or elevated aminotransferase levels except of a worse mean level for factor score anger in POMS scale in patients with persistently normal aminotransferases. No association of quality of life with severity of liver disease was found. Impairment of HRQOL by chronic infection with HCV is similar in patients with PNAL and those with elevated aminotransferase levels.

Comparative Evaluation of Multimedia Driven, Interactive, and Case-Based Teaching in Heart Surgery

BACKGROUND

Multimedia-augmented instruction with various approaches is used in heart surgery. There is little evidence which instructional techniques and media are of advantage to impart knowledge more effectively and lead to better application of knowledge in the operation room.

METHODS

Sixty-nine students learned with an interactive, case-based teaching (ICBT) course about aortic valve replacement. They were compared with historic controls exposed to identical information provided by a multimedia module presenting content systematically (SMM; n = 69) and a print medium (PM; n = 57). Motivation, computer knowledge, and didactic quality were evaluated with psychometric tests. All groups performed multiple choice pretests and posttests and participated in live surgery during which their performance was assessed.

RESULTS

All groups had equal computer knowledge, but the ICBT group felt significantly less-motivated and more challenged. Multiple choice posttest results were comparable (ICBT 80.2% +/- 10.9%, SMM 76.7% +/- 13.3%, PM 76.9% +/- 11.1). During surgery, the ICBT (79.2% +/- 16%) and SMM groups (82.9% +/- 10%) performed significantly better than the PM group (64.7% +/- 12%; both p < 0.0001). Overall didactic assessment was significantly worse in the ICBT group when compared with the SMM and PM groups.

CONCLUSIONS

For novices in heart surgery, ICBT was less motivating than traditionally structured content (SMM and PM). The ICBT did not improve performance in the operation room. However, both multimedia groups could better apply their knowledge during live surgery. The PM is as effective as multimedia when factual knowledge has to be retained.

Development and prospective evaluation of a multimedia teaching course on aortic valve replacement

BACKGROUND

Participation in heart surgery requires procedural and factual knowledge and intensive preparation. There is evidence in the literature that multimedia driven learning has advantages in medical fields where an understanding of complex temporal and spatial events plays an important role. This work describes the development and evaluation of a multimedia driven, online teaching course on aortic valve replacement for students and residents.

METHODS

The instructional model followed a methodological approach with scalable information for different user groups. Various interactive multimedia development tools were employed. In a prospective study, 20 students and 10 residents were exposed to the program in a standardized environment. Both groups completed a 20-item multiple choice pre- and post-test. Psychometric evaluation with HILVE (Heidelberg inventory for the evaluation of teaching courses, 50 items) was performed.

RESULTS

The multimedia course integrates more than 200 high quality surgical video and audio sequences, interactive 2 D and 3 D models, as well as illustrations and text. It is available at www.lamedica.de. Study time in the student group was 103 +/- 11 min and 70 +/- 10 min in the resident group. Mean number of correct responses to the knowledge pre-test was 6.23 +/- 2.71 in the student group and 12.2 +/- 2.66 in the resident group. Mean number of correct responses to the knowledge post-test was 15.24 +/- 2.06 in the student group ( p < 0.0001 vs. pre-test) and 17 +/- 2.98 in the resident group ( p = 0.004 vs. pre-test). The HILVE test showed positive results for teaching conditions, the program's instructional competence, student motivation and individual learning.

CONCLUSION

Our data demonstrate that multimedia driven training can adapt to the individual needs of learners and improves procedural knowledge required for open heart surgery. Consequently, the whole course forms part of the training of residents and students.

Multimedia-driven teaching significantly improves students' performance when compared with a print medium

BACKGROUND

In this study, we compared the educational value of a multimedia module about aortic valve replacement as a preparation for the operating room with a print medium of identical content.

METHODS

One hundred twenty-six students were randomly assigned in a prospective study to either use the multimedia course (n = 69) or a print version (n = 57). A 20-item multiple-choice test was performed before and after learning with the respective medium. Both groups participated in an operation during which they were evaluated with 28 standardized tasks and questions. Individual motivation, computer literacy, and didactic quality of both media were assessed with psychometric tests.

RESULTS

There were no significant differences in the multiple-choice pretest (multimedia, 30.6% +/- 12.4% versus print, 27.9% +/- 11.4%) and posttest responses (multimedia, 76.7% +/- 13.3% versus print, 76.9% +/- 11.1). Mean percentage of correct answers during the operation was 82.9% +/- 10% in the online group and 64.7% +/- 12% in the print group (p < 0.0001). The multimedia group needed significantly (p < 0.001) less study time (105 +/- 24 minutes) when compared with the text group (122 +/- 30 minutes). There were no statistically significant differences in motivation, computer literacy, and didactic quality of either medium.

CONCLUSIONS

Regarding factual knowledge, there is no difference between multimedia-driven learning and a print medium. During heart operations, when understanding of complex temporal and spatial events is essential, students' performance is significantly improved by multimedia-enhanced teaching. The latter further proved to be more efficient in terms of study time.

Cardiac Surgery in a Patient with Haemophilia A

In this report we describe the successful cardiac surgery in a patient with haemophilia A. To undergo to triple on-pump coronary artery bypass grafting the level of factor VIII was estimated to be 100 %, during the operation and the first postoperative week. To reach this level, bolus therapy with B-domain deleted recombinant factor VIII was administered in a low substitution scheme. There was no bleeding complication. The patient discharged on the 14th postoperative day.

Intimal hyperplasia and expression of transforming growth factor-beta1 in saphenous veins and internal mammary arteries before coronary artery surgery

BACKGROUND

The development of fibromuscular intimal hyperplasia and subsequent graft failure remains an urgent problem in cardiac surgery. Transforming growth factor-beta1 (TGF-beta1) is involved in the pathogenesis of arteriosclerosis through induction of extracellular matrix proteins. We tested the hypothesis that intimal hyperplasia is already present in human saphenous veins and left internal mammary arteries before coronary artery bypass surgery and is associated with an increased expression of TGF-beta1.

METHODS

Forty-six segments of saphenous veins and 27 of left internal mammary arteries were collected from 50 patients undergoing coronary artery bypass surgery. Morphometric analysis was performed by microscopic computer analysis. Immunohistochemistry was performed with antibodies directed against TGF-beta1, its latent binding protein (LTBP-1) and its type 2 receptor (RII).

RESULTS

The incidence of intimal hyperplasia was significantly higher in saphenous veins (67.4%) than in mammary arteries (29.6%; p < 0.05). Saphenous veins and mammary arteries with intimal hyperplasia expressed more TGF-beta1 (endothelial and intimal layers) and LTBP-1 (intimal and medial layers) when compared with corresponding vessels without hyperplasia (both groups p < 0.05). Endothelial and intimal RII expression was significantly higher in saphenous veins with intimal hyperplasia as compared with saphenous veins without hyperplasia (p < 0.05). Transforming growth factor-beta1 staining in the intima correlated with the presence of an intimal hyperplasia in saphenous veins (rho = 0.317) and mammary arteries (rho = 0.428).

CONCLUSIONS

Local TGF-beta1 expression is associated with the presence of intimal hyperplasia in the examined vessels. Preexisting intimal hyperplasia is more prevalent and serious in saphenous veins than in left internal mammary arteries, giving further explanation to the superior long-term results of left internal mammary grafts.

Thiazolidinediones reduce endothelial expression of receptors for advanced glycation end products

Advanced glycation end products (AGEs) are critically involved in atherogenesis in diabetes by binding to receptors for AGE (RAGEs) in vascular cells, thus inducing the expression of proinflammatory mediators. In animal models, interruption of the AGE-RAGE interaction reduces lesion size and plaque development. Therefore, limiting RAGE expression might be an intriguing concept to modulate vascular disease in diabetic patients. The present study investigated whether thiazolidinediones (TZDs), antidiabetic agents clinically used to treat patients with type 2 diabetes, might modulate endothelial RAGE expression. Stimulation of human endothelial cells with rosiglitazone or pioglitazone decreased basal as well as tumor necrosis factor-alpha-induced RAGE cell surface and total protein expression. In addition, TZDs reduced RAGE mRNA expression in endothelial cells. These effects on RAGE expression were caused by an inhibition of nuclear factor-kappaB (NF-kappaB) activation at the proximal NF-kappaB site of the RAGE promoter. The functional relevance of reduced RAGE expression was demonstrated by showing that pretreatment of endothelial cells with TZDs decreased AGE- as well as beta-amyloid-induced monocyte chemoattractant protein-1 expression. In conclusion, TZDs reduce RAGE expression in human endothelial cells, thus limiting the cells' susceptibility toward proinflammatory AGE effects. These data provide new insight on how TZDs, in addition to their metabolic effects, might modulate the development of vascular dysfunction in diabetic patients.

Virtual reality and 3D visualizations in heart surgery education

BACKGROUND

Computer assisted teaching plays an increasing role in surgical education. The presented paper describes the development of virtual reality (VR) and 3D visualizations for educational purposes concerning aortocoronary bypass grafting and their prototypical implementation into a database-driven and internet-based educational system in heart surgery.

MATERIALS AND METHODS

A multimedia storyboard has been written and digital video has been encoded. Understanding of these videos was not always satisfying; therefore, additional 3D and VR visualizations have been modelled as VRML, QuickTime, QuickTime Virtual Reality and MPEG-1 applications. An authoring process in terms of integration and orchestration of different multimedia components to educational units has been started.

RESULTS

A virtual model of the heart has been designed. It is highly interactive and the user is able to rotate it, move it, zoom in for details or even fly through. It can be explored during the cardiac cycle and a transparency mode demonstrates coronary arteries, movement of the heart valves, and simultaneous blood-flow. Myocardial ischemia and the effect of an IMA-Graft on myocardial perfusion is simulated. Coronary artery stenoses and bypass-grafts can be interactively added. 3D models of anastomotique techniques and closed thrombendarterectomy have been developed. Different visualizations have been prototypically implemented into a teaching application about operative techniques.

CONCLUSIONS

Interactive virtual reality and 3D teaching applications can be used and distributed via the World Wide Web and have the power to describe surgical anatomy and principles of surgical techniques, where temporal and spatial events play an important role, in a way superior to traditional teaching methods.

Reverse mosaicism in Fanconi anemia: natural gene therapy via molecular self-correction

Fanconi anemia (FA) is a genetically and phenotypically heterogenous autosomal recessive disease associated with chromosomal instability and hypersensitivity to DNA crosslinkers. Prognosis is poor due to progressive bone marrow failure and increased risk of neoplasia, but revertant mosaicism may improve survival. Mechanisms of reversion include back mutation, intragenic crossover, gene conversion and compensating deletions/insertions. We describe the types of reversions found in five mosaic FA patients who are compound heterozygotes for single base mutations in FANCA or FANCC. Intragenic crossover could be shown as the mechanism of self-correction in the FANCC patient. Restoration to wildtype via back mutation or gene conversion of either the paternal or maternal allele was observed in the FANCA patients. The sequence environments of these mutations/reversions were indicative of high mutability, and selective advantage of bone marrow precursor cells carrying a completely restored FANCA allele might explain the surprisingly uniform pattern of these reversions. We also describe a first example of in vitro phenotypic reversion via the emergence of a compensating missense mutation 15 amino acids downstream of the constitutional mutation, which explains the reversion to MMC resistance of the respective lymphoblastoid cell line. With one exception, our mosaic patients showed improvement of their hematological status during a three- to six-year observation period, indicating a proliferative advantage of the reverted cell lineages. In patients with Fanconi anemia, genetic instability due to defective caretaker genes sharply increases the risk of neoplasia, but at the same time increases the chance for revertant mosaicism leading to improved bone marrow function.

The CardioOP-Data Clas (CDC). Development and application of a thesaurus for content management and multi-user teleteaching in cardiac surgery

OBJECTIVES

Self-directed and customized medical education programs are gaining importance in health care instruction. We prototypically implemented a repository-driven online computer system (CardioOP) for teleteaching in Heart Surgery. It supports authoring and multiple re-use of multimedia data for different user groups in different instructional applications and therefore requires a process of content management.

METHODS

We defined objectives for a terminological system to support semantic, cross-media type annotation and retrieval of learning objects: domain completeness, German (natural) language processing, multi-user concepts, extensibility and maintenance, content based annotation and technical implementation. Existing terminologies (ICD10, READ V3, Snomed III, UMLS 1997, MESH) have been analysed according to these objectives.

RESULTS

We found that the analysed terminologies did not meet our criteria sufficiently. Therefore, we developed a domain-specific thesaurus, the CardioOP-DataClas (CDC). The application of the CDC within a database-driven authoring process using specifically developed tools is reported.

CONCLUSIONS

Metadata play an important role in the effective discovery and search, access, integration and management of educational multimedia data in medicine but so far, there is no terminology to support content management for instructional multimedia. We prototypically designed and applied a thesaurus for the CardioOP educational system. Additional work is needed to evaluate the system in terms of user-friend-liness, concept coverage and information retrieval performance.

Increased expression of TGF-beta1 and IGF-I in inflammatory stenotic lesions of hemodialysis fistulas

BACKGROUND

Hemodialysis fistula dysfunction due to stenotic lesions remains a frequent cause of hospitalization for hemodialysis patients. Transforming growth factor-beta(TGF-beta) and insulin-like growth factor-I (IGF-I) are known to be involved in atherogenesis. The latent TGF-beta1 binding protein-1 (LTBP-1) targets extracellular matrix (ECM) interactions and is involved in the regulation of TGF-beta latency.

METHODS

We investigated the expression of TGF-beta1, LTBP-1 and IGF-I in 15 occluded or severely narrowed vein segments of primary arteriovenous fistulas, in 29 non-stenosed control veins from uremic, pre-dialysis patients, and in 15 non-stenosed control saphenous veins obtained from patients undergoing aortocoronary bypass grafting. Immunohistochemistry was performed on snap-frozen tissue specimens using antibodies recognizing either the latency-associated peptide of TGF-beta1 (96-1), LTBP-1 (Ab39) or IGF-I. Serum levels of TGF-beta1 and IGF-I were determined by commercially available IRMA.

RESULTS

In stenosed hemodialysis fistulas, a pronounced intimal thickening with deposition of ECM was observed with light and electron microscopy. Infiltrating cells were seen in stenosed vessels, mostly in areas of intimal hyperplasia and in the media. TGF-beta1, LTBP-1 and IGF-I expression were mostly localized in the neointimal and medial layers, and were significantly higher than in the control groups. A positive correlation between the presence of inflammatory cells and the staining intensity for TGF-beta1, LTBP-1 and IGF-I was found in all vessels analyzed.

CONCLUSION

Neointimal thickening of primary arteriovenous fistulas represents a local inflammatory process and appears to be associated with increased protein expression of TGF-beta1 and IGF-I. While local IGF-I is likely to stimulate smooth muscle cell proliferation in this setting, TGF-beta1 may be an important trigger of ECM production and deposition.

[LaMedica. The medical education academy on the internet]

At present, "modern media" are still a novelty in medical education. The "LaMedica Project"--a program supported by the Federal Ministry for Education and Research--intends to provide an Internet-based education and training system for the entire field of medicine, using all available media resources. This online educational program will provide subjects for medical laypersons as well as medical experts. Various styles of learning and different learning requests will be promoted. The project presented mirrors the cutting edge of database technology, computer-based training and media didactics, critical content processing as well as supplying individual subjects. This report summarizes our 10 months of experience with this program at the Department for Urology and Pediatric Urology of the Johann Wolfgang Goethe University of Frankfurt Main.

Stimulation of nitric oxide synthesis by the aqueous extract of Panax ginseng root in RAW 264.7 cells

1. In this study, we investigated the effect of Panax ginseng root aqueous extracts upon inducible nitric oxide synthesis in RAW 264.7 cells. Panax ginseng root extract has been used in the Asian world for centuries as a traditional herb to enhance physical strength and resistance and is becoming more and more popular in Europe and North America. 2. Incubation of murine macrophages (RAW 264.7 cells) with increasing amounts of aqueous extracts of Panax ginseng (0.05 - 0.8 microg microl(-1)) showed a dose dependent stimulation of inducible nitric oxide synthesis. 3. Polysaccharides isolated from Panax ginseng showed strong stimulation of inducible nitric oxide synthesis, whereas a triterpene-enriched fraction from an aqueous extract of Panax ginseng did not show any stimulation. 4. Inducible nitric oxide synthase protein expression was enhanced in a dose dependent manner as revealed by immunoblotting when cells were incubated with increasing amounts of Panax ginseng extract. This was associated with an incline in inducible nitric oxide synthase mRNA-levels as determined by semiquantitative polymerase chain reaction and electromobility shift assay studies indicated enhanced nuclear factor-kappaB DNA binding activity. 5. As nitric oxide plays an important role in immune function, Panax ginseng treatment could modulate several aspects of host defense mechanisms due to stimulation of the inducible nitric oxide synthase.

Accuracy of beat-to-beat cardiac output monitoring by pulse contour analysis in hemodynamical unstable patients

BACKGROUND

Continuous determination of cardiac output (CO) by transpulmonary thermodilution calibrated pulse-contour analysis is gaining clinicical acceptance. However there is doubt, whether this method is reliable in hemodynamic instable patients. We compared pulse-contour analysis to thermodilution in patients with profound changes of CO.

MATERIAL AND METHODS

24 patients were investigated. CO was measured by thransthoracic thermodilution and pulse-contour analysis in intervals of 60 min during study periods of 8-44 h without recalibration of the pulse-contour computer. Results of 517 measurements were compared by regression, structural regression and Bland-Altman analyses.

RESULTS

Mean change of CO was 40 +/- 27% (range 20-139%), range of systemic vascular resistance was 450 dyn x s/cm(-5) - 2360 dyn x s/cm(-5). Correlation of pulse-contour analysis CO to thermodilution CO was r=0.88 with p=0.0001, bias was 0.2 l/min with 1.2 l/min standard deviation. Mean CO by pulse-contour analysis did not differ significantly from CO by thermodilution during the study period. There were no influences of heart rate or arterial pressure on the difference between both methods.

CONCLUSIONS

CO measurement by arterial pulse-contour analysis is reliable even in patients with profound changes of CO or during hemodynamic instability.

Endocarditis after nipple piercing in a patient with a bicuspid aortic valve

Piercing the skin for cosmetic reasons can be dangerous in young adults who have previously undergone surgery for congenital defects of the heart. We report the case of a 24-year-old man in whom coarctation of the aorta had been corrected 15 years earlier. Two months after piercing his left nipple without antibiotic prophylaxis, he developed a local mastitis, followed by bacterial endocarditits that required replacement of the aortic valve.

Testosterone inhibits expression of inducible nitric oxide synthase in murine macrophages

We investigated the effect of testosterone, the main sexual steroid hormone in men, upon inducible nitric oxide synthesis in murine macrophages. Incubation of murine macrophages (RAW 264.7 cells) stimulated by bacterial lipopolysaccharide (2 microg/ml) with increasing amounts of testosterone (0.1-40 microM) showed a dose dependent inhibition of inducible nitric oxide synthesis. Inducible nitric oxide synthase protein expression was reduced in a dose dependent manner as revealed by immunoblotting when cells were incubated with increasing amounts of testosterone. This was associated with a decline in iNOS mRNA-levels as determined by competitive semiquantitative PCR. As nitric oxide plays an important role in immune defense and atherosclerosis prevention, testosterone-induced iNOS inhibition could lead to an elevated risk of infection as well as to the development of atherosclerotic lesions.

Inhibition of inducible nitric oxide synthesis by the herbal preparation Padma 28 in macrophage cell line

Padma 28 is a mixture of herbs used in traditional Tibetan medicine with anti-inflammatory activities. We investigated the effects of Padma 28 on nitric oxide (NO) production by the inducible nitric oxide synthase (iNOS) in lipopolysaccharide stimulated mouse macrophages (RAW 264.7). Padma 28 (0-900 microg/mL) induced a concentration dependent inhibition of inducible nitric oxide synthesis. iNOS protein expression showed a concentration dependent reduction as revealed by immunoblotting when cells were incubated with increasing amounts of Padma 28. Padma 28 decreased iNOS mRNA levels as shown by RT-PCR. Aqueous extracts from costi amari radix (costus root, the dried root of Saussurea lappa) and the outer cover of myrobalani fructus (the dried fruit of Terminalia chebula), constituents of the complex herb preparation Padma 28, were found to inhibit inducible nitric oxide synthesis by decreasing iNOS protein and iNOS mRNA levels. The inhibition of inducible nitric oxide synthesis might contribute to the anti-inflammatory activities of Padma 28.

CardioOp: an integrated approach to teleteaching in cardiac surgery

INTRODUCTION/PURPOSE

The complexity of cardiac surgery requires continuous training, education and information addressing different individuals: physicians (cardiac surgeons, residents, anaesthesiologists, cardiologists), medical students, perfusionists and patients. Efficacy and efficiency of education and training will likely be improved by the use of multimedia information systems. Nevertheless, computer-based education is facing some serious disadvantages: 1) multimedia productions require tremendous financial and time resources; 2) the obtained multimedia data are only usable for one specific target user group in one specific instructional context; 3) computer based learning programs often show deficiencies in the support of individual learning styles and in providing individual information adjusted to the learner's individual needs. In this paper we describe a computer-system, providing multiple re-use of multimedia-data in different instructional sceneries and providing flexible composition of content to different target user groups.

TOOLS AND METHODS

The ZYX document model has been developed, allowing the modelling and flexible on-the-fly composition of multimedia fragments. It has been implemented as a DataBlade module into the object-relational database system Informix Dynamic Server and allows for presentation-neutral storage of multimedia content from the application domain, delivery and presentation of multimedia material, content based retrieval, re-use and composition of multimedia material for different instructional settings. Multimedia data stored in the repository, that can be processed and authored in terms of our identified needs is created by using a next generation authoring environment called CardioOP-Wizard. High-quality intra-operative video is recorded using a video-robot. Difficult surgical procedures are visualized with generic and CT-based 3D-animations.

RESULTS

An on-line architecture for multiple re-use and flexible composition of media data has been established. The system contains the following instructional applications (prototypically implemented): a multimedia textbook on operative techniques, an interactive module for problem based-training, a module for creation and presentation of lectures and a module for patient information. Principles of cognitive psychology and knowledge management have been employed in the program. These instructional applications provide information ranging from basic knowledge at the beginner's level, procedural knowledge for the advanced level to implicit knowledge for the professional level. For media-annotation with meta-data a metainformation system, the CardioOP-Clas has been developed. The prototype focuses on aortocoronary bypass grafting and heart transplantation.

CONCLUSION

The demonstrated system reflects an integrated approach in terms of information technology and teaching by means of multiple re-use and composition of stored media-items to the individual user and the chosen educational setting on different instructional levels.

Inhibition of inducible nitric oxide synthesis by oxidized lipoprotein(a) in a murine macrophage cell line

Increased plasma levels of human lipoprotein(a) (Lp(a)) are highly correlated with the development of atherosclerotic lesions. During our study, we investigated the effects of native and hypochlorite oxidized lipoprotein(a) (ox-Lp(a)) on nitric oxide production by the inducible nitric oxide synthase (iNOS) in lipopolysaccharide/interferon stimulated mouse macrophages (J774A.1). Ox-Lp(a) (0-2 microg/ml) induces a dose dependent inhibition of inducible nitric oxide synthesis. iNOS protein expression showed a dose dependent reduction as revealed by immunoblotting when cells were incubated with increasing amounts of ox-Lp(a). Ox-Lp(a) decreases iNOS mRNA synthesis as shown by reverse transcription-polymerase chain reaction. Ox-Lp(a) induced iNOS inhibition might contribute to the development of atherosclerotic lesions by reducing the anti-atherogenic effects of nitric oxide.

Urea induces macrophage proliferation by inhibition of inducible nitric oxide synthesis

BACKGROUND

Atherosclerosis is a major cause of morbidity and mortality in chronic renal failure and is associated with the proliferation of macrophages within atherosclerotic lesions.

METHODS

Because the progression of atherosclerosis as a consequence of decreased nitric oxide synthesis has been described, we investigated the correlation between the inhibition of inducible nitric oxide synthase (iNOS) by urea, macrophage proliferation as assayed by cell counting, tritiated thymidine incorporation and measurement of cell protein, and macrophage apoptosis.

RESULTS

Urea induces a dose-dependent inhibition of inducible nitric oxide synthesis in lipopolysaccharide-stimulated mouse macrophages (RAW 264.7) with concomitant macrophage proliferation. Macrophage proliferation, as determined by cell counting, became statistically significant at 60 mM urea, corresponding to a blood urea nitrogen level of 180 mg/100 ml, concentrations seen in uremic patients. iNOS protein expression showed a dose-dependent reduction, as revealed by immunoblotting when cells were incubated with increasing amounts of urea. The decrease of cytosolic DNA fragments in stimulated macrophages incubated with urea shows that the proliferative actions of urea are associated with a decrease of NO-induced apoptosis.

CONCLUSIONS

Our data demonstrate that the inhibition of iNOS-dependent NO production caused by urea enhances macrophage proliferation as a consequence of diminished NO-mediated apoptosis.

Cytotoxic and genotoxic effects of paclitaxel (Taxol) and radiation in a squamous cell carcinoma cell line of the larynx

Paclitaxel (Taxol) is an antimicrotubular agent which blocks the cells in the G2/M phase of the cell cycle. Because of this mechanism it is presumed that this drug could function as a radiation sensitizer. The cytotoxic and genotoxic effects of paclitaxel and a combination of paclitaxel and radiation were studied in the human laryngeal carcinoma cell line HLac 79. The growth of the cells was significantly reduced at concentrations of paclitaxel as low as 10 nM. Flow cytometry data showed a G2/M block after exposure to paclitaxel. Radiation at 12 and 24 h after drug treatment exerted an additive but no radiation sensitizing effect. As genotoxic effect paclitaxel induced multinucleated cells, possibly in a synergistic manner, at low concentrations (10 nM) and radiation doses up to 3 Gy.

[A case-based and multi-media computer learning program on the topic of myocardial infarct, angina pectoris and mitral valve stenosis]

BACKGROUND

Principles in the field of cognitive psychology and problem-based learning together with recent progress in multimedia technologies are providing the basis for the development of case-based and computer-assisted learning systems. With reference to the information-overload of theoretical and factual knowledge in medical education these programs can be an efficient tool to satisfy the current need for new, practical, skill-related forms of knowledge transfer.

METHODS

Apple-Macintosh Computers were selected to develop interactive, multimedia patient-simulations on mitral stenosis, angina pectoris and myocardial infarction.

INSTRUCTIONAL AIM AND CONTENTS

The user acquires knowledge and skills about the leading symptoms, differential diagnoses, the use and analysis of laboratory examinations and the process of diagnostic reasoning while working through the computer-simulated cases.

PEDAGOGICAL DESIGN AND CONCLUSION

Important pedagogical principles associated with computer-assisted learning were employed in the program. Clinical situations can be simulated repeatedly and for every student in an authentic manner. Therefore the program can serve as a preparation for and a supplement to practical clinical education. Compared to conventional teaching media the development of instructional multimedia software requires a tremendous amount of time and resources. Thus, controlled studies are important to objectify the overall advantages such programs can have.

Comparative evaluation of diepoxybutane sensitivity and cell cycle blockage in the diagnosis of Fanconi anemia

Fanconi anemia (FA) is a clinically and genetically heterogenous disease that is usually diagnosed on the basis of chromosomal instability reflecting the hypersensitivity towards the DNA cross-linking agents diepoxybutane (DEB) and/or mitomycin C. A less well-known cellular feature that characterizes FA patients is an intrinsic cell cycle disturbance consisting of prolonged progression through, and arrest within, the G2 phase compartment of the cell cycle. In a collaborative blind study, we have evaluated 72-hour lymphocyte cultures from 66 patients with clinical suspicion of FA both for DEB sensitivity and cell cycle disturbance. A concordant result was obtained in 63 of 66 cases. Each of the 3 discordant, but only 1 of the concordant cases presented with overt leukemia. Seventeen cases were identified as classical FA because of their increased DEB sensitivity and G2 phase blockage. Five cases showed a cell cycle disturbance but only borderline DEB sensitivity. These cases might represent atypical or nonclassical forms of FA. They would have been missed by cell cycle studies without concomitant DEB testing. Used in conjunction, cytogenetic and flow cytometric testing provide for the currently optimal diagnosis of FA in nonleukemic patients.